title: Proviral silencing in embryonic cells is regulated by Yin Yang 1.
abstract: Embryonic cells transcriptionally repress the expression of endogenous and exogenous retroelements. Trim28, a key player in this silencing, is known to act in a large DNA-bound complex, but the other components of the complex are not fully characterized. Here, we show that the zinc finger protein Yin Yang 1 (YY1) is one such component. YY1 binds to the long terminal repeat (LTR) region of both exogenous and endogenous retroviruses (ERVs). Deletion of the YY1-binding site from the retroviral genome leads to a major loss of silencing in embryonic cells and a coordinated loss of repressive histone marks from the proviral chromatin. Depletion of YY1 protein results in marked upregulation of expression of exogenous viruses and of selected ERVs. Finally, we report an embryonic cell-specific interaction between YY1 and Trim28. Our results suggest a major role for YY1 in the silencing of both exogenous retroviruses and ERVs in embryonic cells.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
authors.forename: Sharon
authors.initials: S
authors.lastname: Schlesinger
authors.forename: Andreia H
authors.initials: AH
authors.lastname: Lee
authors.forename: Gary Z
authors.initials: GZ
authors.lastname: Wang
authors.forename: Lisa
authors.initials: L
authors.lastname: Green
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Goff
mesh_terms: D000818:Animals; D001665:Binding Sites; D002843:Chromatin / Q000378:metabolism; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000378:metabolism* / Q000821:virology; D017353:Gene Deletion; D020868:Gene Silencing; D057809:HEK293 Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D051379:Mice; D008979:Moloney murine leukemia virus / Q000235:genetics / Q000378:metabolism; D041681:NIH 3T3 Cells; D009687:Nuclear Proteins / Q000378:metabolism; D011533:Proviruses / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D020079:Terminal Repeat Sequences; D014158:Transcription, Genetic; D000076183:Tripartite Motif-Containing Protein 28; D050986:YY1 Transcription Factor / Q000235:genetics / Q000378:metabolism*
chemical_list: D002843:Chromatin; D004279:DNA, Viral; D006657:Histones; D009687:Nuclear Proteins; D012097:Repressor Proteins; D050986:YY1 Transcription Factor; C103190:Trim28 protein, mouse; D000076183:Tripartite Motif-Containing Protein 28